"We have never allowed posts that promote or encourage suicide or self harm, and will continue to remove it when reported.

"We will not show non-graphic, self-harm related content - such as healed scars - in search, hashtags and the explore tab, and we won't be recommending it."

However Mr Mosseri added that Instagram will not be removing this type of content "entirely" as it wants to support people who need help.

The blog post added: "We don't want to stigmatise or isolate people who may be in distress and posting self-harm related content as a cry for help.

"We want to support people in their time of need - so we are also focused on getting more resources to people posting and searching for self-harm related content and directing them to organisations that can help."

Instagram said its aim is to eventually remove all self-harm and suicide imagery from hashtags, search the explore tab or as recommended content.

After the meeting, Mr Hancock said: "This is an important change, there's lots more things that we need to see, like transparency over how much damaging material there is and also I want to see when people search for material about suicide and self-harm, that they are directed better to help, to the Samaritans, to the NSPCC.

"We've seen progress, the discussions were productive, and the willingness to try and solve this problem.

"What all the companies that I met today committed to was that they want to solve this problem, and they want to work with us about it."

He added that "what really matters is when children are on these sites they are safe" and there is a lot more work to do.

In a statement, Molly Russell's father Ian said he welcomed the changes made by Instagram.

He said the decision "is encouraging to see that decisive steps are now being taken to try to protect children from disturbing content on Instagram and I hope that the company acts swiftly to implement these plans and make good on their commitments."

Mr Russell added: "It is now time for other social media platforms to take action to recognise the responsibility they too have to their users if the internet is to become a safe place for young and vulnerable people."

Mr Mosseri's announcement follows calls by MPs for new laws to hold social media companies to account if they fail to protect young users, according to a report by MPs.